Method and apparatus for producing twisted paper yarn



M y 7, 1968 R. c. SOKOLOWSKI METHOD AND APPARATUS FOR PRODUCING TWISTED PAPER YARN Filed Nov. 14, 1966 2 Sheets-Sheet 1 FIG. I

FIG. 2

FIG. 4

FIG. 3

y 7, 1968 R. c. SOKOLOWSKI 3,381,460

METHOD AND APPARATUS FOR PRODUCING TWISTED PAPER YARN Filed Nov. 14, 1966 2 Sheets-Sheet 2 EFFECT OF TWIST (DRY) m T. 6 m l L w 3 N, i p O mmm PS zokmmkm b TENSILE (IN HUNDREDS OF GRAMS/IN.)

FIG. 5

United States Patent (Mike 3,381,460 METHOD AND APPARATUS FOR PRODUCING TWISTED PAPER YARN Robert C. Sokolowski, Menasha, Wis., assignor to Kimberly-Clark Corporation, Neenah, Wis., a corporation of Delaware Filed Nov. 14, 1966, Ser. No. 593,964 9 Claims. (Cl. 57-31) This invention relates to the production of twisted paper yarn.

It is known to convert paper in roll form into a paper yarn by slitting, moistening and twisting, and then spindling the twisted material. A commercial twisting tissue is available for this purpose. This latter is a glazed material, relatively stiff, and, when formed into a yarn by twisting, requires that the sheet be thoroughly wetted.

Conventional tissue paper such as that employed in facial tissues is unglazed, soft and flexible. .The fibers of such sheets are relatively lightly bonded together, however, and the tissue generally exhibits poor strength characteristics for knitting operations, for example. Wetting of such tissue tends to cause its disintegration.

I have found that conventional tissue paper may be provided with improved strength and yieldability while retaining the desired characteristics of softness and the like if the paper is subjected to a twisting operation in a particular way. This twisting operation may be performed (a) Without wetting the tissue and -(b) While providing for direct feeding of the twisted material to a using machine such as a knitting machine.

This latter feature of my procedure avoids the usual necessity for transfer from bobbins to cones and the like. While I have stressed the utility of my procedure in conjunction with papers of soft texture, my procedure is equally well adapted to conventional glazed tissues and other twisting papers, as will be noted hereinafter. Preferably, however, for reasons which will be apparent, I prefer to use a crepe tissue having a crepe ratio of between about 1.3:1 to 6:1.

=One object of the present invention is to provide a relatively simple method for the production of paper yarn from relatively low tensile strength, soft, porous, pliable tissue paper without significant sacrifice of the porosity, flexibility, softness and the like characteristics desired in many textile materials.

Another object of the invention is to provide an apparatus arrangement for paper yarn twisting which permits constant direct feeding of the twisted yarn to a knitting machine or its device.

The invention will be more fully understood by reference to the following detailed description and accompanying drawings wherein:

FIG. 1 is a schematic elevational view of apparatus useful in the practice of this invention;

FIG. 2 is a plan view illustrating the relationship of elements of the structure shown in FIG. 1;

FIGS. 3 and 4 are, respectively, elevation and plan views of a modification of the apparatus arrangement of FIG. 1; and

FIG. 5 is a graph of tensile versus strength illustrating characteristics of the twisted tissue in accordance with the invention.

Referring to the drawings, the numeral 1 designates (FIG. 1) a package formed of a substantially continuous strip 1a. The package is produced by slitting a web of creped tissue paper lengthwise into a plurality of strips. The fibers of such a web of paper are generally oriented so that a major proportion of the fibers extend longitudinally of the web. The width of the strip 1a is not considered critical and may vary from between about A; inch to 1 inch. A width of /2 inch is typical. The

moisture content of such a strip is commonly between (bone dry basis) about 5 and 12% depending on environment conditions.

As shown in FIG. 1, the package 1 includes a relatively large diameter tube 2 slip fitted on a spindle 3. A plurality of the cylindrical packages are mounted in vertical relation on tube 2. Spindle 3 has a vertical axis 4 coincident with the axes about which packages 1 are wound. Tube 2 is held in position relative to spindle 3 for rotation with the spindle 3 on a support plate 5 by means of a grit plate 6, which latter is simply sandpaper glued to the plate 5. Plate 5 is slidably mounted on spindle 3 for adjustment vertically. A cooperating set screw 7 and key 8 serve this purpose. The arrangement is such that the spindle 3, plate 5 and packages 1 rotate together commonly in the direction indicated by the arrow in FIG. 1. Spindle 3 may be conveniently driven by a conventional electric motor means (not shown) through belt 9 as will be apparent to those skilled in the art.

A ring twister is provided having a cylinder ring track 10 and a traveler 11. Traveler 11 travels about the periphery of ring track 10 in known manner. The direction of rotational movement of the traveler in the practice of the invention is the same as that of the: package, that is, clockwise (FIG. 2). It will be noted that the direction of rotation of the packages 1 is such that a strip extending from traveler 11 to the package would tend to be wound on the package by the package rotation. Specifically, the rotation of the package tends to limit the length of material withdrawn from the package in rotation of the traveler.

The paper strip is unreeled first from upper package 1 in the practice of the invention by applying a drawing force to the strip 1a by winder or windup means generally indicated at 12. Conveniently, the device 12 is simply termed a power wind. As shown in FIG. 1, it incorporates a constant surface speed drum 13 which drives bobbin 14. Bobbin 14 may be independently driven by other known means if so desired. Alternatively, the power wind may be a cone or it may be the needles of a knitting machine. In the preferred practice, the device 12 provides the tension to draw the strip M from the package 1 through the traveler at a controlled rate. The ten sion causes the traveler 11 to rotate about the package 1. The packages 1 are successively withdrawn on an in dividual basis by stopping the device between packages or the packages may be spliced for continuous operation.

The strip 1a in passing from the traveler 11 to the power device 12 is suitably directed to a fixed guide 15, a tensioning member 16, and over pulleys 17, 18 and guide roll 19. It is to be noted that in the practice of the invention the package rotation is opposed to the windup device rotation and that considerable tension exists in the strip 1a.

With the weaker tissues breakage may occur between traveler 11 and guide 15 if sufiicient twist is not imparted to the tissue directly upon leaving the traveler. Commonly, the twist generates promptly and strip breakage is avoided. More breakage appears to occur at the package 1 if the angle of takeoff X (FIG. 2) between a tangent to the package from the traveler and a radial line to the package from the traveler becomes less than about 20. This angle will vary with conditions such as the strength of the tissue, relative speeds and the like. To guard against undue breakage, I prefer to use a relatively large core for the package and to maintain the angle at 20 or slightly greater (off the line between the spindle axis and the traveler ring). It is not necessary that the traveler and the center-line of strip 111 lie in the same horizontal plane. The traveler, however, does ride in a fixed plane for each package but may ride somewhat above the package without detriment to the strip with- 3,381,460: Patented May 7, 1963 f drawal action. While the traveler might ride slightly below the upper surface of the package, such is undesirable as it incerases tension due to friction without any material benefit. The traveler may, of course, be adjusted vertically in known manner to accommodate itself to the package position. As already noted, alternatively the plate 5 may be adjusted to provide the package in appropriate relation to the traveler.

In general, the more twist which is imparted to the paper strip, the greater is the strength of the strip. Also, a greater proportion of twist will cause the configuration of the twisted paper to closely approach the circular and the yarn will then be more readily acceptable by the needles of a knitting machine. Increasing twist, however, tends to reduce the length of twisted yarn which may be handled in a given time, this is, it tends to reduce the output of the machine. Accordingly, the twist should be limited to the lowest amount necessary for subsequent handling of the twisted material. Commonly, 0.5 to 9 twists per inch using a strip of 6 to 18 lbs. per 2880 ft. basis weight is attained. Preferably for most knitting applications, the twist is 6 to 9 turns per inch for each inch taken up by the power wind. Above about 9 turns per inch for some strips the strength tends to fall off, although stretch continues to increase.

The tissue paper as it is originally produced has some inherent stretchability and, if creped, will have a considerable built-in stretch characteristic. Much of this stretch is lost, however, in the slitting and winding operations and in the unreeling from the package 1. Consequently, the strip 1a at the traveler has little residual stretch but the creped material will be more suitable in this respect. The movement of the strip from the package is tangentially of the package and somewhat axially of the package; that is, the strip has a component in the axial direction to attain the twist as it moves to the device 12. The combination of tension and axial movement cause the strip to be twisted (FIG. 1) between the traveler and the guide in a generally known manner. The tension aids compaction in the twisting of the yarn while the spindle rpm. and winder speed determine the turns per inch. This twist tends to decrease strip length and is, therefore, in opposition to the stretch tendency imparted to the strip by the drawing force. However, by the twisting action, significant stretch and strength are provided in the twisted material as may be noted from the curves of FIG. 5.

FIG. 5 illustrated the effect of twisting the paper tissue. Specifically, a crepe tissue of conventional sulfite pulp having a basis weight of 11 pounds per 2880 square feet was formed, slit to several exemplary widths and reeled. The tissue had a crepe ratio of about 1.3 before slitting and an overall stretch at break of about 30%. The slitting and reeling caused a significant loss in stretch and a further loss occurred when unreeling. The spindle speed during unreeling was about 1440 r.p.m. and the traveler speed slightly greater where the traveler was employed. Winder speed was approximately 20 f.p.m.

The winder speed noted above is suitable for small quantity production and laboratory operation. For the purpose of commercial operations I find it desirable to increase winder speed to approximately 120 f.p.m. or greater. For this type of operation the spindle speed also must be increased. To accommodate the traveler to such speed ranges, the traveler ring is driven in the same direction as the traveler. One convenient arrangement is shown in FIGS. 3 and 4 wherein driven spindle 3 carries a gear 20 which meshes with gear 21 carried on shaft 22. Shaft 22 at its upper end mounts gear 23 which cooperates with the ring gear 24- on the outer periphery of cylinder ring 10. By this means the traveler and ring combination may operate at very high speed without undue friction.

Data was obtained (FIG. 5) for unreeling and drawing to provide a comparison of the tapes drawn and wound having 0 and 3, 6 and 9 turns per inch (t.p.i.). In the case of the 0 t.p.i. tape no traveler was employed. Rather, the strip 1a was fed from a common roll type unwind and shaped to obtain conformability to a needle hook. Such shaping is well-known to the art. The shaped tape was passed on a continuous basis to a winder such as is designated at 11 in the drawings. Such shaped material in the attainment of the data of FIG. 5 was subjected to tensile-elongation tests in the same manner as the twisted strands.

As may be seen from FIG. 5, the tensile at break and percent stretch are relatively low. However, by practicing the twisting in accordance with the invention, the stretch in percent is raised materially as is the strength at break. Further, a twisted yarn is obtained which is tight as to twist but soft and flexible as required for knitting and like operations. A twist of 3 turns per inch at a strength of about 800 grams per inch of width of the material nearly doubles the stretch while, at a twist of 6 turns per inch, the stretch is tripled, and about quadrupled at 9 turns per inch.

The tensile data (FIG. 5) was obtained by measuring the tensile of A1 inch, /2 inch, inch and 1 inch material in the flat (untwisted) state after unspindling and winding up. Similarly, the tensile and stretch for the same inch material, for example, were obtained by twisting the A material to the extent indicated and again measuring the tensiles on the twisted yarn. Thus a untwisted tape had a tensile of 209 grams and the strip after twisting (6 t.p.i.) had a tensile of 372 grams. Similarly, stretch increased from 4.7 to about 15.4%. Importantly, however, these desired physical characteristics were obtained without any loss of softness or flexibility or the like significant to a knitting operation or knit materials, for example.

The preferred range for knitting is a percent stretch at break of between about 20-28%. Too high a residual stretch may cause problems at the knitter, too low a residual stretch may cause breakage of the yarn. The extent of the stretch and tensile for a particular purpose may be controlled as is indicated by the subject matter of FIG. 5.

The yarn, since it compacts Well, is tightly drawn and conformable, and may be fed to a using device directly. In some instances it may be combined and fed with other yarns either for strength or decorative purposes, if so desired.

In general, the paper subject to the procedure described is largely unchanged as to flexibility, softness, absorbency and the like by the twisting. Consequently, where a soft product is desired, my described procedure serves the purpose since tissue papers are readily available which have these characteristics. Most suitably, crepe tissue is employed to attain the greater softness qualities. The tissue may, of course, carry a wet strength treatment if such is desired in a final product, but a wet strength property is not a requirement of the process described.

The apparatus itself may be varied considerably while attaining the necessary twist. While I have referred to a traveler, it is clear that the usual fiyer or driven flyer may be accommodated to the purpose; basically, it is only necessary that provision may be made for withdrawal off the end, as it is termed in the trade, in order to attain the twist. Also, it is clear that by varying the feet per minute speed of the winder 10, the twist may be changed simply by maintaining the unreelin g spindle speed constant.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

What is claimed is:

1. A method of twisting a tissue paper strip into yarns which comprises unreeling the paper strip from a package by applying a drawing force to the strip, and twisting 5 the strip while driving the package in such a direction as to oppose the drawing force and to tend to reel the strip .on the package.

2. A method according to claim 1 in which the paper strip is creped tissue.

3. A method according to claim 1 which includes the step of feeding the twisted strip directly to a knitting machine to apply said drawing force.

4. A method according to claim 1 in which the moisture content of the strip throughout the process is in the range of about 5 to 12% based on the bone dry weight of the tissue.

5. A method according to claim 1 in which the width of the strip is in the range of about /8 inch to 1 inch.

6. A method according to claim 1 in which the twist imparted to the strip is in the range of about 0.5 to 9 turns per inch.

7. Apparatus for producing paper yarn comprising: spindle means and associated means for carrying a package of strip material in rotation on the spindle means, driving means for rotating said spindle means in such a direction as to wind strip material on said spindle means, power wind means for withdrawing strip material from said spindle means by applying tensive forces to strip material, and means interposed functionally between said spindle means and said power wind means for twisting strip material as it is pulled from said spindle means to said power wind means against the rotation of the spindle means.

8. Apparatus according to claim 7 wherein the means interposed between the spindle means and the power wind means includes a ring traveler and a ring track supporting the traveler and which ring track is positively driven in rotation in the same direction of movement as the traveler, said ring track being disposed around said spindle means.

9. Apparatus according to claim 8 wherein the ring track and the spindle means are each driven and the rotational speeds of the track and spindle means are a fixed ratio.

References Cited UNITED STATES PATENTS 795,776 7/1905 Kron 57-167 974,132 11/1910 Funke 5731 1,062,796 5/1913 Rabe 5731 1,134,379 4/1915 Gunther 57-31 2,948,102 8/1960 Baucom 57-59 3,145,524 8/1964 Dewelle 5731 XR 3,292,356 12/1966 Hinds 57-59 3,302,380 2/1967 Meulen 57-31 FOREIGN PATENTS;

317,958 3/1918 Germany.

319,993 5/1918 Germany.

357,730 5/1920 Germany.

716,950 1/ 1942 Germany.

FRANK J. COHEN, Primary Examiner.

D. WATKINS, Assistant Examiner. 

7. APPARATUS FOR PRODUCING PAPER YARN COMPRISING: SPINDLE MEANS AND ASSOCIATED MEANS OR CARRYING A PACKAGE OF STRIP MATERIAL IN ROTATION ON THE SPINDLE MEANS, DRIVING MEANS FOR ROTATING SAID SPINDLE MEANS IN SUCH A DIRECTION AS TO WIND STRIP MATERIAL O N SAID SPINDLE MEANS, POWER WIND MEANS FOR WITHDRAWING STRIP MATERIAL FROM SAID SPINDLE MEANS BY APPLYING TENSIVE FORCES TO STRIP 